# gmat.txt

 Number of different arrangements of n objects in a row n! Number of different arrangements when objects are repeated TotalObjects! / (Number!Of!Each!Repeated!) Picking groups, where order doesn't matter (If 3 of 7 standby passengers are selected for a flight, how many diff. combos of standby passengers can be selected?) Factorial of the total / (Factorial of group 1 * Factorial of group 2) 7! / (3!x4!) Permutation where order matters, repetition is allowed (# of permutations of a 3 digit lock?) n^r (3^3, or 3x3x3) Order matters, no repetition allowed (How many different orders of 3 balls selected from 16?) n! / (n-r)! - choose r things out of n 16! / (16-3)!, or 16! / 13! Combination where order DOESN'T matter, repetition is not allowed (like a lottery) n! / (r![n-r]!) n is number of things to choose from, you choose r Combination where order DOESN'T matter, you can repeat (picking scoops of ice cream) (n+r-1)! / (r![n-1]!) n is number of things to choose from, you choose r of them Probabilty that X AND Y both occur Multiply probabilities together Probability that independent event X OR event Y will occur Add probabilities together Probability of event X OR event Y, which can occur together P(X) + P(Y) - P(X+Y) AuthorAnonymous ID142465 Card Setgmat.txt DescriptionGMAT review Updated2012-03-19T13:36:20Z Show Answers